Window treatment accessory



FIG. 1 is an environmental perspective view with the broken line showingof a partial curtain, curtain rod and bracket are for illustrativepurposes only and form no part of the claimed design;

FIG. 2 is a top plan view thereof the bottom plan view, the front viewand the rear view being mirror images of the top plan view;

FIG. 3 is a right side view thereof; and,

FIG. 4 is a left side view thereof.

The ornamental design for a "window treatment accessory," as shown anddescribed.